This invention relates to a hand tool and more particularly to a hand tool which is extensible for obtaining improved leverage.
Some hand tools, such as ratchet wrenches, have extended arms to provide leverage in loosening or tightening nuts or other members. In some cases, the presence of corrosion requires a very high torque to loosen or tighten the member
It is possible to extend the arm length of the tool sufficient to obtain any maximum torque which could conceivably be required, but this makes the tool unwieldy large and bulky for every day use when the additional torque is not required.
A number of United States Patents have been issued for tools which have extensible arms. The following are examples of such patents.
U.S. Pat. No. 2,382,291 shows an extensible hand tool relying on a split ring as a holding member.
U.S. Pat. No. 2,963,930 discloses an extensible torque bar which relies on a ball mounted in a sleeve which slides.
U.S. Pat. No. 3,306,639 describes an extensible torque rod which relies on a roller mounted in a sleeve and drops into slots on the rod.
U.S. Pat. No. 4,070,932 provides an extendible handle for a tool in which a spring mounted sleeve is locked in place by a set screw.
U.S. Pat. No. 4,440,517 discloses an adjustable torque-multiplier breaker bar which relies on a pair of balls to drop into slots in a sleeve.
U.S. Pat. No. 4,409,866 shows a tool handle with a trigger member with a leg to lock a handle in place.
U. S. Pat. No. 4,581,958 has an extensible handle assembly relying on a ball falling into a groove to set the handle length and provision to lock the extensible member on the handle.
U.S. Pat. No. 4,586,406 discloses an extendible wrench relying on detent pins to hold the extendible member in place.
The arrangements appearing in the preceding patents are complex and costly to make, and, in addition, they do not appear to be designed for ease of separation of the extensible portion or repair None of these patents teaches the present invention.